1. Field of the Invention
The present invention relates to a video signal selector and a medical image filing system therewith, and particularly relates to the video signal selector that automatically selects one of an endoscopic video signal and another medical video signal such as an ultrasonic video signal and the medical image filing system therewith.
2. Description Related to the Prior Art
In endoscopy, a flexible slender tube of an electronic endoscope is introduced into patient's body from his/her mouth or the like to look inside the body. In recent years, endoscopic ultrasonography (EUS) is commonly known, in which an ultrasonic transducer provided at a distal end of the tube applies ultrasonic waves to an internal body part, and receives reflected waves therefrom to form an image. The EUS can visualize an inner wall of an organ in its thickness (penetration) direction. Accordingly, the EUS is preferably used in examination of, for example, the digestive system including esophagus and duodenum, for the purpose of precisely finding out the depth of a lesion such as cancer and ulcer cells.
A medical image filing system for the EUS is generally constituted of an ultrasonic endoscope, an endoscopic video signal processor, an ultrasonic video signal processor, a monitor and a video server. The ultrasonic endoscope has the ultrasonic transducer and an image sensor such as CCD at a distal end of an insert section. The endoscopic video signal processor produces an endoscopic video signal from a pickup signal of the image sensor. The ultrasonic video signal processor produces an ultrasonic video signal from a detection signal of the ultrasonic transducer. The monitor receives the endoscopic video signal and ultrasonic video signal, and selectively or simultaneously displays endoscopic video and ultrasonic video on its screen. The video server obtains the endoscopic or ultrasonic video signal, and saves part or whole of the signal as a still image or moving images. Instead of the ultrasonic endoscope, a combination of an ultrasonic probe and the electronic endoscope may be used. In this case, the ultrasonic probe is inserted into a medical instrument insertion port of the electronic endoscope, and protrudes from a distal end of an insert section to emit ultrasonic waves inside the patient's body.
In the medical image filing system, the video server requires two-channel input for the entry of both of the endoscopic and ultrasonic video signals. The video server, however, just has single channel input in most cases. Preparing a video server with the two-channel input brings about increase in equipment cost of a hospital.
Thus, a switch was conventionally provided between the video signal processors and the video server. In response to manual operation with a dial, button or the like, the switch selects one of the endoscopic video signal and ultrasonic video signal, and inputs the selected signal into the video server. Providing the switch enables the use of the conventional video server with the single-channel input, and hence prevents increase in equipment cost (refer to Japanese Patent Laid-Open Publication No. 10-211201).
In the above system, however, there was the possibility of human error, e.g. forgetting switching operation. For example, while the switch is selecting the endoscopic video signal, the ultrasonic video signal is never written into the video server even if an ultrasonic image capture command is issued. The human error causes mis-recording of the image. The recorded image is checked after completion of the examination, so that the mis-recording of the image results in re-examination.